Korg Forums

[mikelees]

I found a great use for the Kronos SPDIF inputs to make an inexpensive digital audio bridge for sampling VSTs on a Mac, and thought I would share it...

When sampling VSTs with a Mac, the problem is creating an audio bridge between the sampling software (e.g. Sample Robot) and the VST. Up until now, I have been using a hardware solution of 2 audio interfaces back to back, which means that the audio goes via an analogue path (adds noise), and it's hard to get the gain right, so that either samples aren't too quiet, or I end up with clipping, hence I've been looking for a way to do this digitally and not worry about noise or gain. There are software solutions (e.g. Rogue Amoeba Loopback), but these are expensive. I found an inexpensive way to do this using the Mac optical output, and the SPDIF on Kronos that just needs 2 cables (Toslink and USB).

On some 2015 and earlier Macs (e.g. my 2015 MacBook Pro), there is a Toslink optical out available through the 3.5mm headphone jack (see here for which models: https://support.apple.com/en-gb/HT202730). On other Macs or PCs, the Behringer UCA222 or 202 are a cheap way of getting an optical Toslink output.

Using the Toslink out, it's possible to set-up an all-digital audio bridge from the Mac to the Kronos SPDIF, then back out through the Kronos USB to the Mac again. The signal path is: VST -> Mac Built-in output -> Toslink 3.5mm cable -> Kronos SPDIF input -> Kronos L/R USB output -> Mac USB -> Sampling software. This isn't using any of the Kronos sounds or control - it's simply a way of getting a digital audio bridge from the VST to the sampling software on the Mac.

The 3.5mm Toslink / SPDIF cable is inexpensive and easily available from Amazon. I used this one: https://www.amazon.co.uk/FosPower-Toslink-Digital-Connectors-Strain-Relief-Gold/dp/B00T8HWUVS/ref=sr_1_1?ie=UTF8&qid=1548850441&sr=8-1&keywords=3.5mm+toslink+cable. If you're going direct from the Mac headphone port, then you need a 3.5mm (Mini Toslink) to standard Toslink cable, if using a Behringer UCA202/222, then you would need a standard Toslink cable.

The way to set it up is:
1. Connect the Toslink cable from the Mac to the Kronos SPDIF input.
2. Connect a standard USB cable from the Mac to the Kronos USB B port.
3. Set the VST host to output audio from the Mac Built-In Output. Set the sample rate to 48kHz (Kronos native rate).
4. On the Kronos, go to Global mode, Audio tab, and make sure that the SPDIF L/R inputs are routed to the Kronos L/R output, volume is 127 and balance is fully left / right for the left and right channels. You can also disable the Kronos analogue audio inputs here to minimise any noise.
5. Set the sampling software audio input to Kronos USB. Again, set the sample rate to 48kHz, stereo.
6. To get MIDI data from the sampling software to the VST host, you need to set up a virtual MIDI port on the Mac. This can be done as the instructions here: http://www.johanlooijenga.com/tools/12-virtual-ports.html. Set the sample software MIDI out port and the VST host midi in port to use the virtual port.
7. Start sampling! You should now have an all-digital audio bridge from the VST host to the sample software. You can monitor the sampling using the Kronos main L/R or headphone outputs.
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[SeedyLee]

Good tip, but I’m pretty sure you can achieve the same thing just with a single USB cable.

Just set your VST to output to the Kronos, then On the Kronos set the incoming USB to go the main L/R. In Sample Robot, you can then just record from the Kronos.

Also, it’s just been announced that SampleRobot Pro is going to have native VST host features to achieve the same thing, which will be awesome!
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Current Equipment:
Korg Kronos 2 88, Reface CS, Roland JV-1080, TE OP1, Moog Subsequent 37, Korg ARP Odyssey, Allen & Heath Zed 18, Adam F5, MOTU MIDI Express XT, Lexicon MX200 & MPX1, Yamaha QY700, Yamaha AW16G, Tascam DP008ex, Zoom H6, Organelle, Roland J6 & JU06A

Previous: Triton LE 61/Sampling/64MB/4GB SCSI, MS2000BR, Kronos 1 61, Monotribe, NanoKontrol, NanoKeys, Kaossilator II, Casio HT3000, Roland VP-03, Reface DX, Novation Mininova, MPC One

[mikelees]